Interaction between mass changes of the Antarctic Ice Sheet and solid Earth in Dronning Maud Land, East Antarctica

• Applicant: Dr.-Ing. Mirko Scheinert
• Subject Area: Geodesy, Photogrammetry, Remote Sensing, Geoinformatics, Cartography ; Geophysics
• Term: from 2018 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 404719077

This project aims to determine the deformation of the Earth’s crust in the Atlantic sector of East Antarctica, by geodetic GNSS measurements with improved spatial resolution and over a long time span of partly more than 20 years. The response of the solid Earth to present and past ice-mass changes shall be estimated, namely the instantaneous elastic response and the glacial-isostatic adjustment. The renewal proposal is based on an updated plan to carry out repeated GNSS measurements in western and central Dronning Maud Land (DML) as well as in the region of Molodeshnaya, Enderby Land. Glacial-isostatic adjustment (GIA) still exerts the greatest uncertainty when determining the mass balance of the Antarctic Ice Sheet by satellite gravimetry. The only direct measurement of the GIA effect can be obtained by realizing geodetic GNSS measurements on bedrock. As investigated so far, the vertical deformation pattern is not uniform across Antarctica. DML and, at least to a certain extent, Enderby Land are areas where comparably small deformation signals are expected but measured so far by only a few geodetic GNSS sites. The group of the applicant initiated campaign-style geodetic GNSS measurements in DML in 1995, and in Enderby Land in 2007. Most of these sites are situated in the mountain ranges that run parallel to the coast about 100 to 200 km inland as well as in coastal areas like Schirmacher Oasis and Oasis Molodeshny. Given the long time span of 15 years and more, it is timely to repeat the geodetic GNSS measurements. We expect to determine the vertical deformation rate with an accuracy of down to a few mm/a. For this, we aim to investigate in detail the effect of temporal and spatial correlations on the adjusted deformation rates and associated uncertainties when using the differential GNSS processing. Subsequently, the GNSS-inferred vertical deformation rates will serve as constraints for an improved GIA determination. The GIA effect will be estimated in two ways: First, satellite altimetry and gravimetry will be combined to empirically estimate ice-mass balance and GIA. Second, by close cooperation with partners from AWI, the 3D rheological structure of the Earth will be revised and, subsequently, introduced into GIA predictions. Special attention will be given to improve consistency in applying rheological parameters in the calculation of both the instantaneous elastic deformation and GIA. Thus, we aim to contribute to the currently ongoing discussion within the scientific community on how the physical processes in the Earth’s interior can be captured in a better way, to learn about their complexity, and to gain an improved understanding of the interaction between ice-mass changes and solid Earth that is reflected by GIA and related sea-level change.

• DFG Programme: Infrastructure Priority Programmes
• Subproject of: SPP 1158: Antarctic Research with Comparable Investigations in Arctic Sea Ice Areas - with renewal proposal 2025 - 2030
• Co-Investigators: Dr. Graeme Eagles; Dr. Ingo Sasgen